SparkseeNet  5.1.0
Public Member Functions | List of all members
com.sparsity.sparksee.gdb.QueryStream Class Reference

Query stream interface. More...

Public Member Functions

bool Start (com.sparsity.sparksee.gdb.ResultSetList list)
 Starts the stream. More...
 
bool Fetch (com.sparsity.sparksee.gdb.ValueList list)
 Gets the next row and moves the iterator forward. More...
 
bool Prepare (com.sparsity.sparksee.gdb.ValueList list)
 Prepares the stream before it is started. More...
 

Detailed Description

Query stream interface.

A QueryStream is the interface between the application and the STREAM operator. When the operator starts inside a Query, the method is prepared with query-defined arguments. Then, if there are input operations, the STREAM operator builds the ResultSets and starts the iteration. Finally, the operator fetches rows until no more are available.

Application exceptions must be cached by the subclass that implements the interface.

Author
Sparsity Technologies http://www.sparsity-technologies.com

Member Function Documentation

bool com.sparsity.sparksee.gdb.QueryStream.Fetch ( com.sparsity.sparksee.gdb.ValueList  list)

Gets the next row and moves the iterator forward.

The end of sequence is denoted by returning TRUE with an empty row. A valid row must contain as many values (even NULL) as expected by the query.

Parameters
list[out] Storage for the new rows
Returns
TRUE if there is a row or end of sequence, FALSE on error
bool com.sparsity.sparksee.gdb.QueryStream.Prepare ( com.sparsity.sparksee.gdb.ValueList  list)

Prepares the stream before it is started.

Parameters
list[in] Optional list of arguments
Returns
FALSE on error
bool com.sparsity.sparksee.gdb.QueryStream.Start ( com.sparsity.sparksee.gdb.ResultSetList  list)

Starts the stream.

Parameters
list[in] Optional list of input ResultSets
Returns
FALSE on error